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	<script type="text/javascript">
	     var num=parseInt(prompt("请输入一个三位数"));
	     var baiwei=parseInt(num/100);
	     var shiwei=parseInt(num%100/10);
	     var gewei=parseInt(num%10);
	     var sum=baiwei+shiwei+gewei;
	     alert(sum);
	 </script>
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